<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    {% if age < 18 %}
        <p>未成年</p>
    {% elif age == 18 %}
        <p>正好成年</p>
    {% else %}
        <p>您大于18岁了!</p>
    {% endif %}
</body>
</html>